CPU (4.0 GHz) Bottlenecking GPU (GTX 770)

Matthew-san · May 8, 2014

I had my FX-8320 overclocked to 4.0 GHz and I believe it was bottlenecking my EVGA GTX 770. In a graphically intense area of Tomb Raider I experienced a severe FPS drop, going from an average of 50 fps to 15-25 (Ultra Settings -Tress FX on). I didn't understand why this was occurring but the most prominent thought in my mind was that my 8320 was bottlenecking my GPU since the 770 is a high-end card. I restarted my computer, increased the clock ratio and the frequency of my CPU to an overall speed of 4.32 GHz, and reloaded the area as was at on Tomb Raider.

I had absolutely no lag, and I was probably getting a consistent 50 fps. Can anyone tell me why this phenomenon occurred? Is it even possible for my CPU (running at 4 GHz) to bottleneck my 770 in a game like Tomb Raider?

paulbatzing · May 8, 2014

Try this: http://forums.eidosgames.com/showthread.php?t=136427&page=2
It is supposed to make more cores usable.

MagicPants · May 8, 2014

Tress FX is made to work better on Radeon cards. You probably saw your massive slow down while Lara's hair was filling a lot of the screen.
If you want to verify the CPU bottleneck, try clocking it back down and see if you get the performance issue again (it could be a onetime time, like a windows update running in the background)

blockhead78 · May 8, 2014

while the 8320 is a decent CPU, they don't handle physics as well as intel chips

If it was down to something like Lara's hair filling a lot of the screen, it will be physics.

Physics are dealt with by the CPU rather than GPU

By increasing your CPU clock you've given the CPU some extra power to deal with the physics better.

I see exactly the same on my 8350 with 3dmark.

With a lower clock I see a big drop in physics scores, as soon as my 4.8ghz clock is applied, my physics scores go up

Matthew-san · May 8, 2014

Hey thanks for the link. Tomb Raider is working perfectly fine for now so hopefully I won't have to apply any self-patches. Nixxes, the developer representative of the site, said to use caution when applying the patch because it has been know to severely corrupt the hardware of Nvidia oriented computers. Also, I was in area where I could realistically see how a low or mid-range PC could struggle but certainly not mine. It was really odd, since it has only happened once and with my CPU overclocked to 4.0. Hopefully no one else will experience the same issue I did. I was lucky enough to have a good CPU, with plenty of cores, and an aftermarket cooler already installed, other people might not be so fortunate.

Matthew-san · May 8, 2014

I understand what you mean MagicPants and blockhead78 about the Tress-FX enabled. When the camera is zoomed on Laura's hair the fps drops a little bit but not enough to affect the overall experience of the game. Without Tress-FX disabled I usually get around 60 fps on average. I'll give your idea a shot MagicPants about setting my CPU speed back to 4.0 GHz and see if the same performance dive occurs.

paulbatzing · May 8, 2014

One more comment: I can not find it now, but I read that map detail is really slowing down the cpu in big areas in this game. Might be something to consider, since it does not change the graphics quality as much as turning of Tress-FX...

chris987 · May 8, 2014

your cpu is fine and there isnt any issue. bottleneck would occure in all games not just one. tressFx is already killing performance on most AMD gpu so on nvidia better have it disabled. it is like trying Physx on Radeon. it will just not work!

Matthew-san · May 8, 2014

Interesting, can I disable the map from the options menu? I'd like to see if I get an increase in fps.

Matthew-san · May 8, 2014

Lol chris987, I believe that the TressFX will run decently enough on High-end Nvidia gpu's. Of course, a lot of it has to do with physics so I imagine that's mostly handled by the CPU instead. It's too bad I don't have a Intel Core i7 4770K installed, I could do some real damage with that.

paulbatzing · May 8, 2014

Here: http://www.tomshardware.co.uk/answers/id-1935944/tomb-raider-fps-drop-low-gpu-usage.html

Matthew-san · May 8, 2014

Sounds good, I'll try turning off the map. It looks amazing on ultra at 50 fps but if it jumps to 60 or 70 then that would be awesome!

Thanks everyone for all the help, my problem seems to be fixed for now, but just in case, check back on this thread every now and again because I might run into the same problem.

Matthew-san · May 8, 2014

Wow, you were right paulbatzing. I didn't find out how to get rid of the map but I did disable exclusive full screen and I got a pretty large performance increase. With exclusive full screen I got this:

Minimum FPS: 29.1
Average: 52.1
Max FPS: 61.2

With exclusive full screen disabled:

Minimum FPS: 46.2
Average: 57.6
Max: 62.2

Not a huge difference but it's well worth disabling exclusive full screen because I can see no reason for it except for taking power from the CPU and GPU lol.

paulbatzing · May 8, 2014

great to hear it

Matthew-san · May 8, 2014

It's amazing how much you can improve a game just by messing around with the settings. I removed the V-sync and ran the benchmark and got a minimum of 46, an average 69.8, and maximum of 94 lol. Sometimes I envy console gamers, like when my game was lagging for no apparent reason, and then at times like now I'm reminded of why I chose PC gaming.

Thanks again for your help!

iLead · May 16, 2014

Are there any other games you play that might be CPU-intensive. Right now my FX-6300 doesn't like BF4 that much even though it is clocked at 4.5 GHz , but I'm using Mantle.

Matthew-san · May 16, 2014

My Norton security warns me when my CPU usage is at 100% and I've had several games reach that point. Crysis 3, Assassin's Creed IV, and Rome II are the usual culprits. My games all run fine for me, even at 100% CPU usage, except for that time with Tomb Raider. I haven't played BF4 yet but I plan on it soon and I'm sure it'll probably use my CPU's full power. It's not that uncommon anymore for current games to push a CPU to its max.

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